Plunger switch with coiled spring contactor



Nov. 12, 1968 E. w. VOLAND 3,410,975

PLUNGER SWITCH WITH COILED SPRING CONTACTOR Filed Dec. 1, 1965 INVENTOR ELMO W. VOLAND BY 2 E2 ATTORNE United States Patent 3,410,975 PLUNGER SWITCH WITH COILED SPRING CONTACTOR Elmo W. Voland, Indianapolis, Ind., assignor to RR. Mallory & Co. Inc., Indianapolis, Ind., a corporation of Delaware Filed Dec. 1, 1965, Ser. No. 510,914 6 Claims. (Cl. 200-166) ABSTRACT OF THE DISCLOSURE A coil spring contactor rests transversely atop a V- shaped groove in a switch housing. A plunger deforms the spring into the groove when actuated, causing the spring to move in relation to a pair of terminals. In one version of the switch, the spring moves out of contact with the terminals when the plunger is actuated; in another version, the spring moves into contact with the terminals.

The present invention relates to plunger switches and more particularly to the means and method for providing a new and novel construction for such switches.

Contemporary plunger switches usually have numerous and unlike mating parts which add to the cost of the switch and which tend to make the switch unreliable. Also, most plunger switches are somewhat bulky and require rivets or eyelets for their assembly.

The present invention is a plunger switch which is comprised of a housing which is formed of two identical portions, two identical terminal members which are secured within said housing, a single coil spring contact member, and a plunger. The two identical portions of the housing are fastened together by snap-in pins which are integrally formed on said portions. Hence, there are only six parts in the plunger switch of the present invention. Obviously, the manufacturing cost of such a switch is significantly reduced.

It is an object of the present invention, therefore, to provide a plunnger switch which is small, light, reliable, inexpensive to manufacture, and easy to assemble.

It is another object of the present invention to provide a plunger switch having a coil spring contact memher which electrically connects a pair of fixed terminal members.

It is another objet of the present invention to provide a plunger switch wherein there is a coil spring contact member for connecting a pair of fixed terminal members and a plunger means for depressing said coil spring contact member into a V-shaped cutout in the housing of said switch, thereby disconnecting said pair of fixed terminal members.

It is another object of the present invention to provide a plunger switch wherein the-re is a coil spring contact member which is wound so as to have a high initial tension with free ends. The initial tension provides good electrical contact with the terminal members of said plunger switch.

The present invention, in another of its aspects, relates to novel features of the instrumentalities described herein for teaching the principal object of the invention and to the novel principles employed in the instrumentalities whether or not these features and principles may be used in the said object and/ or in the said field.

Other objects of the invention and the nature thereof will become apparent from the following description considered in conjunction with the accompanying drawings and wherein like reference numbers describe elements of similar function therein and wherein the scope of the invention is determined rather from the dependent claims.

For illustrative purposes, the invention will be described 3,410,975 Patented Nov. 12, 1968 ice in conjunction with the accompanying drawings in which:

FIGURE 1 is an exploded perspective view of the plunger switch of the present invention.

FIGURE 2 is a fragmentary view of the plunger switch of the present invention showing the plunger in a deenergized position.

FIGURE 3 is a fragmentary view of the plunger switch of the present invention showing the plunger in an energized position.

Generally speaking, the present invention is an electrical switch comprising: a housing; a pair of fixed terminal members mounted in said housing; a coil spring contact member for electrically connecting said pair of fixed terminal members, said contact member being disposed so as to be adjacent to a V-shaped cutout in said housing; and a means for depressing the center of said contact member into said V-s-haped cutout so as to cause the ends of said contact member to move away from said fixed terminal members, thereby electrically disconnecting said fixed terminal members. The means for depressing said contact member can be a plunger which is slidably mounted within said housing. The coil spring contact member is wound so as to have a high initial tension when both of its ends are free.

Referring now to the drawing, and particularly to the exploded perspective view of FIGURE 1, the component parts of the present invention can be visualized in conjunction with the following description. The bottom portion of the housing 10 is formed of anly suitable in sulating material and is adapted to be mated with the top portion of the housing 11 which is also formed of any suitable insulating material. The top portion of the housing 11 and the bottom portion of the housing 10 are identically formed so as to only require one mold for manurfacturing purposes. There are two identical terminal members 13 and 14 which are held in place by the bottom portion of the housing 10 and the top portion of the housing 11. There is a coil spring contact member 15 which is also held in place by the bottom portion of the housing 10 and the top portion of the housing 11. Finally, there is a plunger 12 for deflecting the coil spring contact member 15.

The bottom portion of the housing 10 and the top portion of the housing 11 are held together by means of the snap-in pins 16 which are inserted into the holes 17. The snap-in pins 16 are integrally formed in the top and bottom portions of the housing. (The snap-in pins 16 for the top portion of the housing 11 cannot be seen in FIGURE 1.)

The terminal members 13 and 14 are adapted to fit into the cutouts 18 in the bottom portion of the housing 10 and the top portion of the housing 11.

There is a V-shaped cutout 19 in the bottom portion of the housing 10 and the top portion of the housing 11 which is directly under the center portion of the coil spring contact member 15. The purpose of this V-shaped cutout will be discussed later in the specification.

There is a mounting hole 20 in the bottom portion of the housing 10 and the top portion of the housing 11 to provide a means for mounting the plunger switch.

The plunger 12 moves in an out of the opening 21 in the bottom portion of the housing 10' and the top portion of the housing 11.

Referring now to FIGURE 2, a view of the plunger switch with the plunger 12 in a deenergized position can be seen. The coil spring contact memebr 15, which is a high initial tension coil spring, is held by the plunger 12 so as to make electrical contact with the terminal members 13 and 14. The coil spring contact member 15 is plated with a suitable contact material so as to make proper contact with the terminal members 13 and 14.

Referring now to FIGURE 3, a view of the plunger switch with the plunger 12 depressed can be seen. The coil spring contact member 15 is forced into the V-shaped cutout 19 so as to cause the ends of said contact member 15 to pull away from the terminal members 13 and 14. The initial tension of the coil spring contact member 15 and the speed of depressing the plunger 12 will determine the breaking speed for the contact between the coil spring contact member 15 and the terminal members 13 and 14. Also, the fact that the contact member 15 is a coil spring will provide a wiping action as said contact member is contacted with the terminal members 13 and 14. The depth and angle of the V-shaped cutout 19 can be varied to suit the particular coil spring contact 15 used.

The basic mechanism of the plunger switch described in this specification can be varied to accommodate several ditferent requirements. For instance, the coil spring contact member 15 and terminal members 13 and 14 arrangement could be reversed so that electrical continuity between said terminal members would occur only when the plunger 12 is depressed. Likewise, an extra pair of terminal members could be added above the terminal members 13 and 14 so that said extra terminal members would be interconnected when the plunger 12 is depressed.

The coil spring contact member 15 could be depressed by a lever member or other means as well as the plunger 12. It is for this reason that the plunger 12 will be referred to as a means for depressing said coil spring contact member 15 into the V-shaped cutout 19.

The plunger switch of the present invention, as hereinbefore described in one of its embodiments, is merely illustrative and not exhaustive in scope. Since many widely different embodiments of the invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description and shown in the accompanying drawing shall be interposed as illustrative and not in a limiting sense.

What is claimed is:

1. An electrical switch comprising: a housing; a pair of fixed terminal members mounted in said housing; a coil spring contact member for electrically connecting said pair of fixed terminal members, said contact member being disposed so as to be adjacent to a V-shaped cutout in said housing; and a means for depressing the center of said contact member into said V-shaped cutout so as to cause the ends of said contact member to move in relation to said terminal members.

2. An electrical switch as in claim 1 wherein said means for depressing the center of said contact member into said V-shaped cutout is a plunger which is slidably mounted within said housing.

3. An electrical switch as in claim 1 wherein said means for depressing the center of said contact member into said V-shaped cutout is a plunger which is slidably mounted within said housing, said plunger also being a means for biasing said contact member against said terminal members, thereby assuring proper electrical contact.

4. An electrical switch as in claim 1 wherein said housing is formed of two identical portions which are held together by snap-in pins which are integrally formed on said portions.

5. An electrical switch as in claim 1 wherein said coil spring contact member is wound so as to have an initial tension when both ends of said contact member are free.

6. An electrical switch as in claim 1 wherein said means for depressing the center of said contact member into said V-shaped cutout causes the ends of said contact member to move away from said fixed terminal members, thereby electrically disconnecting said fixed terminal members.

References Cited UNITED STATES PATENTS 1,333,115 3/1920 Jones. 2,816,181 12/1957 Mann et a1.

FOREIGN PATENTS 829,965 3/1960 Great Britain.

ROBERT K. SCHAEFER, Primary Examiner.

H. BURKS, Assistant Examiner. 

